1 files changed, 19 insertions, 2 deletions
diff --git a/src/win32/cairo-win32-surface.c b/src/win32/cairo-win32-surface.c
index 7cd46fc60..e6862bd10 100755..100644
--- a/src/win32/cairo-win32-surface.c
+++ b/src/win32/cairo-win32-surface.c
@@ -172,6 +172,21 @@ cairo_win32_surface_get_dc (cairo_surface_t *surface)
 }
 
 /**
+ * _cairo_surface_is_win32:
+ * @surface: a #cairo_surface_t
+ *
+ * Checks if a surface is an #cairo_win32_surface_t
+ *
+ * Return value: %TRUE if the surface is an win32 surface
+ **/
+static inline cairo_bool_t
+_cairo_surface_is_win32 (const cairo_surface_t *surface)
+{
+    /* _cairo_surface_nil sets a NULL backend so be safe */
+    return surface->backend && surface->backend->type == CAIRO_SURFACE_TYPE_WIN32;
+}
+
+/**
  * cairo_win32_surface_get_image:
  * @surface: a #cairo_surface_t
  *
@@ -187,8 +202,10 @@ cairo_win32_surface_get_dc (cairo_surface_t *surface)
 cairo_surface_t *
 cairo_win32_surface_get_image (cairo_surface_t *surface)
 {
-    if (surface->backend->type != CAIRO_SURFACE_TYPE_WIN32)
-	return NULL;
+
+    if (! _cairo_surface_is_win32 (surface)) {
+        return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));
+    }
 
     GdiFlush();
     return to_win32_display_surface(surface)->image;